DE69535688T2 - Optical semiconductor module and method for its production - Google Patents

Description

The The invention relates to a method for producing an optical semiconductor module, wherein the optical coupling of a semiconductor optical element and an optical waveguide must be adjusted.

On In the field of optical fiber communication becomes an optical semiconductor module used in which optical semiconductor elements, i. H. a laser diode (a light-emitting element) or a light-sensing element, etc., acting as a signal transmission path serve, optically coupled, and the optically coupled semiconductor elements and the optical fiber in a housing with airtight seal (hermetic seal).

The EP 0331331A discloses a known type of optical semiconductor module having a semiconductor base with a variety of etched features and metallization patterns for mounting the optoelectronic device. Another example of a semiconductor mounting base having such etched features will be described in U.S.P. EP 0418423A shown.

These Type of optical semiconductor module is much more expensive than a semiconductor module in which electronic semiconductor elements, such as For example, transistors and ICs are packed. this is not because the fabrication of a semiconductor optical element is high Costs, but mainly, because the cost of adjusting the optical coupling of an optical Semiconductor element and an optical waveguide, such as an optical fiber, because of the difficulty in improving the throughput are high.

In Generally need a semiconductor optical element and an optical fiber having a Accuracy in the order of magnitude be positioned by micrometers. Positioning by mechanical Means, such as a guide mechanism or the like, has a drawback that a mounting base on which the semiconductor elements are attached, with great Accuracy and complexity must be handled, and therefore the basic manufacturing costs considerably elevated.

Around overcome this disadvantage be at a conventional optical semiconductor module, an optical semiconductor element and a single optical fiber on independent Bases or holders attached. The semiconductor element and the optical Fiber on the independent Bases or holders are tested separately, and the bases or holders face each other, whereby the optical coupling is reached. For this reason, mechanical positions need of the optical semiconductor element and the optical fiber become. In this case, a so-called optical coupling adjustment required, with mounting positions to be set while the intensity an optical input or output is monitored.

The optical semiconductor element, as described above, must by a housing be sealed airtight so as to reliably ensure that a light input / output surface of the optical semiconductor element can be protected. The airtight Sealing is achieved by sealing an airtight sealing element, made of metal, glass, ceramics or the like, achieved with direct bonding (fusion bonding) of metal or glass. Out this reason, the sealing step requires a fairly high temperature, and the airtight sealing element is thermally deformed very much.

at a conventional one optical semiconductor module is an optical semiconductor element with an optical fiber optically coupled after the semiconductor element is sealed airtight. If the optical coupling before the sealing step carried out will, can the mechanical positions are shifted, because the airtight Sealing element readily by heat in the sealing step is deformed. In this case, it is difficult because the optical Semiconductor element that has been sealed optically to the optical Fiber must be adjusted, the mounting position of the optical Semiconductor element due to the airtight sealing element mechanically capture. In other words, it is difficult because the positioning is not through a guide mechanism can be achieved, a time required for the step is, by rough adjustment of the positions of the optical axes of the optical semiconductor element and the optical fiber by mechanical To reduce funds. Therefore, the adjustment of the optical axis, generally an accuracy of the order of microns requires, completely be performed by optical position detecting means.

Further, after adjusting the optical axis, it is necessary to use the semiconductor element and the op mechanically secure the fiber in order to prevent displacement of the optical axis. However, the optical axis may be displaced during the mechanical fastening because the positional relationship between the members to be fixed is changed depending on the optical axis set state, and the state changes even under the same process conditions.

As As described above, in the conventional optical semiconductor module the throughput due to the difficulty for the step of adjusting The time required to reduce the optical coupling, not without be further improved. Furthermore the production yield can not be easily improved, because the positional relationship between the to be mounted in each module Elements is different. Accordingly, the cost of hiring the optical coupling increases, which leads to very high module costs.

Under these circumstances is there a need for an optical semiconductor module whose production yield without Further improved and that can be mass produced. Some Investigations for Such an optical semiconductor module has been proposed. From The investigations have an optical semiconductor module by application of so-called micromachining, one of the semiconductor manufacturing processes, public Attention excited. Because that by the application of micromachining produced module with a high degree of accuracy machine-processed can be, d. H. in the order of magnitude of submicrons, can the positions of a semiconductor optical element and an optical Fiber with the accuracy of the order of magnitude of micrometers set only by mechanical assembly become what overcomes a basic problem of the conventional semiconductor module. In other words, the optical coupling of a semiconductor optical element and an optical fiber only by a mechanical assembly step be achieved, and the adjustment of the optical axes, as is described above is not required. Also, as a number of bases in the same way as in the case of preparation the optical semiconductor elements can be mass produced, the costs for the processing of mounting bases compared to the conventional ones Cutting work by a machine considerably reduced.

With the above method can the price for the generation of optical semiconductor modules are reduced, and the manufacturing yield can be significantly improved. Further can signal transmission with a big one capacity and a high quality, what kind of the optical communication method is characteristic, such as an optical interconnection, are introduced in industrial machinery. As a result, a system with high speed and high Achievement to be built, which is very much to the development and the Progress of the industry contributes.

at the optical semiconductor module to which the micromachining process However, since only the improvement of the considered optical coupling will, another request for the practicality, d. h., an airtight seal, not reached. For this reason, such an optical semiconductor module far from a practical application. Disadvantages of the conventional Technique will be described below with reference to the drawings.

1 Fig. 10 is a cross-sectional view of an example of the conventional optical semiconductor module to which micromachining is applied. As it is in 1 is shown, the optical semiconductor module comprises a Si substrate 1 , an optical fiber 5 , an optical semiconductor element 6 , an IC 7 for driving the optical semiconductor element 6 and a bonding wire 17 , The module also includes an airtight sealing cap 28 a position adjusting groove 2 , an airtight sealing solder 10 for connecting the airtight sealing cap 28 with the Si substrate 1 , the airtight sealant 16 , a solder 18 for the optical semiconductor element 6 on the Si substrate 1 , an electrical wiring conductor 26 and an electrically non-conductive material 27 ,

In this example, the optical fiber is 5 at the position adjusting groove 2 of the Si substrate 1 attached so that the positional relationship of the optical semiconductor element 6 mechanically self-aligned. Therefore, the optical coupling through the mechanical assembly steps of the mounting of the optical semiconductor element 6 on the Si substrate 1 and inserting the optical fiber 5 in the position adjusting groove 2 be achieved. The reason why the mounting base of the Si substrate 1 is formed, is that the Positionseinstellnut 2 can be machine processed by the above-mentioned micromachining.

In general, since a monocrystalline (single-crystalline) Si substrate can be anisotropically etched due to crystal orientation, it can be processed into various geometric shapes. A typical shape of a groove for the optical semiconductor module is a so-called V-groove having inclinations of the (111) planes on both sides, which are obtained in a case where a slit-like mask is formed in a <110> or <-110> direction on the crystalline (100) plane. Monocrystalline Si has a property that the plane (111) is etched much more slowly than the crystalline planes (100) and (110) when etched by means of an aqueous solution of KOH or hydrazine. The reference numerals (100), (110) and (111) indicate the crystalline plane. The reference numerals <110> and <-110> denote the crystal axis.

In the above-mentioned anisotropic etching, a V-groove can be easily formed by using the crystal orientation, and the mask used in the etching can be formed in the conventional semiconductor process. Thermally oxidized SiO ₂ obtained by heat-treating an Si substrate in an oxide atmosphere or Si ₃ N ₄ obtained by the CVD method (Chemical Vapor Deposition method) is used as a mask in etching. It is absolutely possible that the machine processing accuracy obtained by the system is as low as 1 μm, depending on the etching conditions and the mask setting.

As described above, the optical semiconductor module to which the micromachining is applied is effective for omitting the adjustment of the optical coupling. Since the main purpose of such a module is to omit the adjustment of the optical coupling, an airtight sealing mechanism of the optical semiconductor element is not necessarily considered. Although there have not been many proposals to solve the problems of the airtight sealing mechanism, an example of the solutions is found in PROCEEDING of 42nd ELECTRONIC COMPONENTS & TECHNOLOGY CONFERENCE (1992), page 94, 1 , excited. In this example, an airtight sealing cap for sealing a mounting region of a semiconductor optical element is mounted on an Si substrate formed by the micromachining process, thereby achieving a partial airtight seal on the Si substrate. This example is applied to the above-mentioned optical semiconductor module using micromachining, so that the in 1 shown structure can be easily obtained

With of the above structure the optical semiconductor element and the optical fiber by mechanical Assemble optically coupled together, and an airtight Sealing of the optical semiconductor element can be achieved. As a result, can the price for reduces the production of optical semiconductor modules and the Manufacturing yield can be significantly improved, so the above described effects can be obtained.

However, the optical semiconductor module thus obtained, which still has disadvantages from the viewpoint of practical use, can not be used in practice. More specifically, in the structure of 1 used a Si substrate as a mounting base to make the best use of advantages of the semiconductor process method. However, if the airtight sealing cap 28 is formed of a metal selected to ensure hermiticity, the thermal expansion property of the Si substrate does not necessarily correspond to that of the other elements. Further, if a number of electrical wiring conductors 26 is required, for example, when optical fibers are arranged in arrays and some ten guide lines of wiring conductors 26 are required, the thermal strain voltage applied to the Si substrate is not negligible since the area of the Si substrate is increased due to the increase in the number of wiring guides and the accumulated amount of thermal deformation of the wiring guides. The thermal deformation causes problems such as a crack of the Si substrate or a package leakage due to the deterioration of the mechanical strength of the airtight seal portion. Such a problem tends to lower the reliability of the optical semiconductor module. As a result, the yield is lowered in consideration of the reliability, and the advantage of simplifying and reducing the optical coupling step is lost.

The above problem of low reliability arises mainly from the mechanical fragility of Si, the material of the substrate. Therefore, if the substrate is similar to the general semiconductor package Made of ceramic, the problem becomes low reliability reduced. However, if the substrate is made of ceramic, arise different problems, and the essential task of the Improvement of the module is missed. Because the crystal anisotropy for example during the etching process can not be used is the accuracy of the etching process as low as a few tens of microns. Besides, the cost of the Material of the substrate increases, or the thermal conductivity of the substrate is lowered. Therefore, it is necessary to mechanical Machinability priority to give that is necessary to adjust the optical Omit axis in the optical semiconductor modules. For this Reason, the use of a Si substrate is essential.

As described above, the conventional optical semiconductor module has a limit in Ver cost reduction due to optical axis adjustment, whereas application of the micromachining process as a means of reducing cost lacks practicality.

at the conventional one Semiconductor packages is the thermal strain applied to the Si substrate not negligible, because the area of the Si substrate due to the increase in the number of wiring guides and the accumulated amount of thermal deformation of the wiring guides elevated becomes. The thermal deformation leads to problems such as a crack of the Si substrate or a housing leakage due to deterioration of the mechanical strength of the airtight sealing portion. Such a problem tends to increase the reliability of the optical semiconductor module lower. As a result, the yield can be taken into consideration the reliability be reduced by simplification and reduction of the advantage obtained in the optical coupling step has been lost.

The Invention was considered the above problems of the conventional ones Technology performed. Accordingly, there is a first object of the invention therein, a method for generating of an optical semiconductor module, cracking of the monocrystalline substrate due to thermal strain avoids due to the airtight sealing element, so that the productivity and the reliability can be improved.

The above tasks can by a method of producing a semiconductor optical module in accordance can be achieved with claim 1.

According to one are produced by the invention, optical semiconductor module, since the optical semiconductor element having the optical waveguide body, such as For example, an optical fiber, only by mechanical Assembling can be optically coupled, the cost of adjustment the optical axis is not required and the reliability the airtight sealing structure is ensured. As well as a high reliability is obtained even if the module structure as a connection type can be formed with optical connector, can be a reliable optical Semiconductor module can be produced with a high productivity. thats why the invention advantageous because the manufacturing cost considerably be reduced and the scope widened. Further can if force in one direction to the monocrystalline substrate to bend, to the substrate due to the voltage of the airtight Sealing element is applied, the bend by the reinforcing body or the reinforcing element be reduced or balanced on the rear surface of the monocrystalline substrate is formed. Therefore, the monocrystalline Substrate do not crack.

These Invention can be more complete from the following detailed Description in conjunction with the accompanying drawings be in which show:

1 a cross-sectional view of a conventional optical semiconductor module;

2 a cross-sectional view of a semiconductor optical module, which is useful for understanding the invention;

3 to 5 perspective views of reinforcing elements;

6 a schematic diagram, the one in the module of 2 used Si substrate shows;

7A and 7B Diagrams showing a first example of the anisotropic etching of Si according to the invention;

8th a cross-sectional view taken along the line XX in 6 taken;

9 a cross-sectional view taken along the line XI-XI in 6 taken; and

10 an exploded view of parts of the optical semiconductor module of 2 ,

embodiments The invention will be described with reference to the accompanying drawings described.

An example of an optical semiconductor module useful for understanding the invention includes a Si substrate 1 ie a mounting base as in 2 is shown. An optical semiconductor element 6 and a IC 7 for transmitting or receiving data to or from the optical semiconductor element are on a surface of the Si substrate 1 attached over solder. An optical axis alignment mechanism becomes on the surface of the Si substrate 1 formed by the known semiconductor processing method. The optical axis alignment mechanism includes a guide groove 2 an optical fiber 5 a portion for fixing the mounting position of the optical semiconductor element 6 , a metallization and the like. The Si substrate 1 includes a solder groove 3 that with airtight sealing solder 10 is filled, which is an optical fiber 5 surrounds.

The optical semiconductor module comprises a reinforcing plate 8th to thermal deformation of the Si substrate 1 to prevent. As in 3 is shown is the reinforcing plate 8th a box with a surface of the soil 8a for receiving the Si substrate 1 and walls on the three sides of the floor. One end of the reinforcement plate 8th has no wall, so optical fibers 5 can be pulled out. The reinforcement plate 8th does not have to be plate-shaped, but may be of prism-shaped reinforcing elements. A structure, as in 4 or 5 can be shown as the reinforcing plate 8th be used.

The optical semiconductor module of this example comprises an airtight sealing element. The airtight sealing element is above the Si substrate 1 and the reinforcing plate 8th arranged. The airtight sealing element comprises a lower frame 11 , an airtight, electrically non-conductive sealing material 12 , an electrical signal pin 13 , an electrically non-conductive sealing material 14 , an upper frame 15 and an airtight sealing cap 16 ,

In the optical semiconductor module of this example, the electric signal pin is 13 from the first end portions of the Si substrate 1 and the reinforcing plate 8th extended. The electrical signal pin 13 is with the IC 7 through a bonding wire 17 connected. The optical semiconductor element 6 is with the IC 7 also through a bonding wire 17 connected. The optical semiconductor element 6 is with the optical fiber 5 optically coupled.

In this example, the Si substrate having a mechanism for mechanically adjusting the optical axis is on the reinforcing plate 8th attached, and the airtight sealing element is provided thereon. With this structure, the optical semiconductor element becomes 6 by sealing the bottom of the airtight sealing element with the Si substrate 1 sealed airtight. The thermal deformation of the Si substrate 1 and the upper frame 15 of the airtight sealing element is achieved by using a suitable material and a suitable structure of the reinforcing element 8th minimized.

The following table shows the combination of the materials of the reinforcing plate and the sealing member (the sealing cap, the upper frame, the lead frame, the electrically non-conductive sealing material and the lower frame). The following case A is used as the reinforcing plate and the sealing member of this example. TABLE element Case A Case B Case C reinforcing plate Metal (Kovar) ceramics Metal (Kovar) sealing cap Metal (Kovar) Ceramic or metal (Kovar) thermoplastic or metal (Kovar) Upper frame Metal (Kovar) Not Metal (Kovar) or not electrically non-conductive sealing material Glass ceramics thermoplastic lead frame Metal (Kovar) Metal (Kovar) Metal (Kovar) electrically non-conductive sealing material Glass ceramics thermoplastic Lower frame Metal (Kovar) Not Metal (Kovar)

• (1) Entweder Metall oder Keramik kann als die Verstärkungsplatte verwendet werden. Die Kombination der Verstärkungsplatte aus Keramik und des oberen Rahmen aus Metall oder die Kombination der Verstärkungsplatte aus Metall und des oberen Rahmen aus Keramik kann verwendet werden.
• (2) Der Zuleitungsrahmen, der aus einem Metall gebildet ist, ist ein elektrischer Leiter. Kovar (Ni: 29%, Co: 17%, Fe: Rest) wird am gewöhnlichsten als die klebende Dichtmasse verwendet. Eine Ni-Fe-Legierung (Ni: 42%, Fe: Rest) oder eine Kupferlegierung, die eine geringe Menge von Cr und Zr enthält, kann jedoch ebenfalls verwendet werden.
• (3) Aluminiumoxid (Al₂O₃) oder Aluminiumnitrid (AlN) kann als Keramik verwendet werden.
• (4) EVOH, PVdC, PCTFE, oder LCP können als thermoplastische Kunststoff verwendet werden.
• (5) Wenn Keramik verwendet wird, wird ein Abschnitt der mit Metall zu verbindenden Keramik metallisiert und danach mit dem Metall hartgelötet oder gelötet.
• (6) Wenn thermoplastischer Kunststoff verwendet wird, ist es lediglich notwendig, dass der Kunststoff geformt wird, um das Substrat abzudecken, und ein besonderer Bondprozess ist nicht erforderlich.
• (7) Die obige Kombination der Verstärkungsplatte und des Dichtelements sollte bestimmt werden, sodass die thermische Ausdehnungseigenschaft des Si-Substrats 1 und jene der Verstärkungsplatte und des Dichtelements gut ausgeglichen sind.

General requirements for the materials of the reinforcing plate and the sealing member of the invention and notes on the above table are described below.

• (1) Either metal or ceramic can be used as the reinforcing plate. The combination of the ceramic reinforcing plate and the metal upper frame or the combination of the metal reinforcing plate and the ceramic upper frame may be used.
• (2) The lead frame formed of a metal is an electric conductor. Kovar (Ni: 29%, Co: 17%, Fe: balance) is most commonly used as the adhesive sealant. However, a Ni-Fe alloy (Ni: 42%, Fe: balance) or a copper alloy containing a small amount of Cr and Zr may also be used.
• (3) Alumina (Al ₂ O ₃ ) or aluminum nitride (AlN) can be used as ceramics.
• (4) EVOH, PVdC, PCTFE, or LCP can be used as thermoplastic.
• (5) When ceramic is used, a portion of the ceramic-to-be-bonded ceramic is metallized, and then brazed or brazed to the metal.
• (6) When using thermoplastic resin, it is only necessary that the plastic is molded to cover the substrate, and a special bonding process is not required.
• (7) The above combination of the reinforcing plate and the sealing member should be determined so that the thermal expansion property of the Si substrate 1 and those of the reinforcing plate and the sealing member are well balanced.

A thermal deformation of the Si substrate 1 and the airtight sealing element ( 11 to 16 ) generally occurs in an assembling step of an optical semiconductor module or reflow soldering step in the process of mounting the module on a printed circuit board. However, even after the module is mounted on the circuit board, it may occur due to an internal temperature distribution on the device to which the circuit board is mounted or a change in the ambient temperature.

The simplest method of suppressing the thermal deformation due to the distribution or change of temperature is as follows: using the same material to make the parts ( 11 to 16 ) of the airtight sealing element, in particular the frame 11 and 15 and the airtight sealing cap 16 (which are generally formed of metal), wherein the reinforcing plate 8th is made of the same material and the same shape as the airtight sealing element ( 11 to 16 ), and the airtight sealing member and the reinforcing plate 8th in the sections that are opposite each other. With this method, the thermal deformation between the airtight sealing element ( 11 to 16 ) and the substrate Si occurs due to the thermal deformation occurring between the reinforcing plate 8th and the Si substrate 1 occurs, balanced. As a result, the problem of the conventional technique, ie, cracking of the Si substrate or housing leakage due to fatigue of the airtight seal portion, does not easily occur.

In this case, however, the thermal resistance tends to be between the Si substrate 1 and the reinforcing plate 8th to be high, since the reinforcing element 8th with the Si substrate 1 only in contact under the airtight sealing section. To prevent this, it is possible to use the reinforcing plate 8th completely in contact with the lower surface of the Si substrate 1 to bring, as in 2 is shown, whereby the thermal resistance is lowered, and the material and the thickness of the reinforcing plate 8th and adjust the properties of the solder. As a result, the thermal deformation can be compensated in the same manner as in the above-mentioned method.

As in the cross section of the airtight sealing section in FIG 2 (perpendicular to the plane of 1 ), the rear end and the side ends of the reinforcing plate 8th directly with the lower frame 11 the airtight sealing element are bonded. With this structure, the deformation between the airtight sealing member and the reinforcing plate 8th balanced directly, which increases the degree of freedom in the design to minimize the thermal deformation. In addition, since the Si substrate 1 is not exposed to the exterior of the housing, its protection ensured.

7A and 7B Fig. 15 are perspective views mainly showing the Si substrate 1 show which is to be mounted on the optical semiconductor module. A metallization pattern 4 to make a soldered connection with the airtight sealing element 11 to reach is on the Si substrate 1 educated. The metallization pattern 4 is formed by patterning by deposition of Au / Pt / Ti and liftoff. The optical semiconductor element 6 and the IC 7 are mounted on a pad metal having the same structure as that of the metallization pattern s4 and a solder (an Au-Sn solder formed by multilayer deposition of Au and Sn) formed on the Si substrate then subjected to a heat treatment, whereby the element 6 and the IC 7 is connected to the substrate. In this process, it is possible to use a so-called flip-chip mounting method in which the elements to be mounted on the substrate are positioned by using the surface tension of molten solder the. The solder well 3 has to cause the solder on the back of the optical fiber 5 flows when the airtight sealing element is soldered to the substrate. The solder well 3 becomes by anisotropic etching of Si in the same manner as in the process of forming the guide groove 2 for adjusting the position of the optical fiber.

Examples of the method for forming the patterns of the guide groove 2 and the solder well 3 who cross each other are referring to 7A and 7B described. In the following, the portions already described will be identified with the same reference numerals as those used above, and their detailed descriptions will be omitted.

7A shows the shape of a mask, and 7B shows the shape of the resulting etched sections 308 . 309 , The narrower section ( 307 ) of the mask is for forming the guide groove 2 and the wider section ( 306 ) is the solder well 3 ,

7A and 7B show a case in which the wider groove 308 first with the mask 306 etched and then the narrower groove 309 with the mask 307 is formed. In this case, since the wider groove is first formed independently even if the bottom of the groove is not completely etched to be surrounded by (111) planes, no etching deformation occurs unless the mask for forming the second Groove is not broken. However, it is necessary that the mask pattern of the narrower groove should not intersect that of the wider groove, but instead a much narrower groove is formed in one end portion of the narrower groove to connect with the inclining surface of the wider groove.

As a result, a projection in the mask 307 the narrower groove is formed, and an undercut is formed under the mask. However, the back etching region is stopped by a (111) plane extending from the narrower groove on an extension line of a longer side of the mask 307 extends. At this time, it is necessary that the distal end of the narrowest groove pattern on the (111) plane on the side of the wider groove 306 is arranged and from one end 309 the bottom of the narrower groove 307 protrudes toward the side of the wider groove, so as not to reach the bottom of the wider groove to the deformation of the bottom of the wider groove 308 to prevent, as described above. In this way, a substantially complete composite groove is formed, as in FIG 7B is shown.

8th and 9 FIG. 15 are cross-sectional views of the Si substrate as described above, at a plane perpendicular to the plane of FIG 2 ,

8th shows a cross section in a section of in 6 shown Lötmittelnut 3 , and 9 shows a cross section in a section of the IC 7 for transmitting or receiving data to or from the optical semiconductor element. As described above, the side ends of the reinforcing plate become 8th with the lower frame 11 bonded to the airtight sealing element. 2 and 8th clearly show that the upper surface of the Si substrate 1 is sealed airtight. In particular, it is obvious, as in 8th shown is that the optical fiber 5 out through the sealed portion in the solder groove 3 to be led. Thus, the optical semiconductor element becomes 6 and the optical fiber 5 with each other on the Si substrate 1 optically coupled by the mechanical positioning, whereby airtightness of the optical semiconductor element 6 and the mechanical strength of the Si substrate 1 is guaranteed.

Thus, the optical semiconductor element is 6 sealed airtight, and the Si substrate 1 is structurally reinforced without creating additional manufacturing costs for the adjustment of the optical axis. It is therefore possible to produce a reliable optical semiconductor module at a low cost.

In addition, it is possible because the Si substrate 1 , which is a precision-processed element that can be mass-produced by semiconductor processes that produce optical semiconductor modules in bulk without limitation through the throughput or cost of precision-processed elements.

A process for producing the above optical semiconductor module will be described. 10 is an exploded view of the in 2 shown example. Details of the elements, such as the semiconductor element, are not shown or described below.

In 10 has the lower frame made of a Kovar alloy 11 a partially modified optical fiber insertion section. The electrically non-conductive sealing materials 12 and 14 are made, for example, from a low melting point glass. The electrical signal pin 13 , the upper frame 15 and the airtight sealing cap 16 , as well as the lower frame 11 , be out made of kovar alloy.

Because the lower frame 11 has the modified portion as shown in FIG 10 is shown in the 6 shown Lötmittelnut 3 corresponds, the optical fibers can be soldered as shown in FIG 8th is shown. If the lower frame 11 the modified section does not have the sealing solder 10 be quite thick to achieve an airtight seal, in which case the solder material may flow out or the width of the soldered portion may vary from place to place. Also, since the bottom frame 11 tends to be with the optical fiber 5 to be brought into contact, without further tension on the optical fiber 5 created when the module is assembled. In an extreme case, the optical fiber 5 damaged or cut off, in which case the reliability and yield of the module are lowered. The same problem arises in a case where the optical fiber is replaced by an optical waveguide.

The process of assembling the module is as follows. First, the bottom frame 11 , the electrically non-conductive sealing materials 12 and 14 , the lead frame (the electric signal pin) 13 and the upper frame 15 accumulated together and subjected to a heat treatment, whereby the above-mentioned airtight sealing member is formed as a unit. Then, the semiconductor optical element 6 , the IC 7 and the optical fiber 5 successively or simultaneously on the Si substrate 1 by, for example, soldering attached. A preform solder 9 , the Si substrate 1 , the airtight sealant 10 and the airtight sealing element (made from the parts 11 to 15 existing accumulated element) are successively accumulated, and the preform solder 9 and the sealant 10 are brought to melt at the same time. After that, the semiconductor element and the electric pin become 13 wire bonded and then the sealing cap 16 sealed by seam welding. As a result, the optical semiconductor module is obtained as shown in FIG 2 is shown.

As As has been described above, the optical semiconductor element can be used with an optical waveguide, such as an optical waveguide Fiber, optically coupled, and the optical semiconductor element can be airtight only by a mechanical assembly process be sealed. Furthermore can, since the reinforcement plate on the back surface of the Si substrate, the Si substrate is torn due to cracking the tension of the airtight sealing cap are prevented. The invention allows a reduction in the manufacturing cost of the semiconductor module, a significant improvement in the productivity of it and a guaranteed Reliability. The invention also enables that a signal transmission with big ones capacity and high quality, the for the optical communication technology has been characteristic on general industrial equipment can be applied.

Claims (1)

A method for producing an optical semiconductor module, characterized in that a composite pattern of a combination of grooves having different widths on a (100) plane of an Si substrate ( 1 ) is formed by anisotropic etching, wherein the etching is stopped substantially at the (111) plane, and thereafter an optical fiber ( 5 ) is attached to the composite pattern, characterized in that the method comprises the following sequential steps: forming a wider groove by etching on the Si substrate ( 1 ) with a first rectangular window mask; and forming a narrower groove for supporting an optical fiber by etching on the Si substrate ( 1 with a mask comprising a second rectangular window spaced a predetermined distance apart from the wider groove, and further comprising a band-shaped window narrower than the second rectangular window and extending from an oblique surface on a contact portion of the wider one Groove extends to the second rectangular window.